KR20210014199A - A semiconductor processing system, and a method of implanting ions into a workpiece, a method of processing a workpiece, a method of etching a workpiece, and a method of depositing material on the workpiece - Google Patents

Abstract

A system is disclosed having an auxiliary plasma source disposed proximate a workpiece for use with an ion beam. The auxiliary plasma source is used to generate ions and radicals that can drift towards the workpiece and form a film. The ion beam is then used to provide energy so that the ions and radicals can process the workpiece. Additionally, various applications of the system are disclosed. For example, the system can be used for a variety of processes including deposition, implantation, etching, pre-treatment and post-treatment. By placing the auxiliary plasma source close to the work piece, processes that were not previously possible can be performed. Additionally, two dissimilar processes such as cleaning and injection or injection and passivating can be performed without removing the workpiece from the end station.

Description

Systems and methods using inline surface engineering sources

This application claims priority to U.S. Patent Application Serial No. 16/015,323, filed June 22, 2018, the disclosure of which is incorporated herein by reference in its entirety.

Embodiments of the present disclosure relate to semiconductor processing systems and methods using an inline surface engineering source, and more particularly, to a source of ions and radicals proximate a workpiece for use with an ion beam. It's about use.

The fabrication of semiconductor devices involves a number of individual and complex processes. One such process may be an implantation process in which a dopant material is implanted into the workpiece. Another process may be a deposition process in which the material is deposited on the workpiece. Another process may be an etching process in which material is removed from the work piece.

In order to direct the ions along the desired path, a beam line system with multiple components such as electrodes, mass spectrometers, quadrupole lenses, and acceleration/deceleration stages is used. Like an optical system, a beamline system manipulates the ions by bending the path of the ions and focusing the ions.

In some embodiments, a ribbon ion beam is generated. The ribbon ion beam is an ion beam that is much wider than its height. In other words, the aspect ratio of a ribbon ion beam, defined as its width divided by its height measured at the workpiece, can be very high, for example greater than 20. In some embodiments, the width of the ribbon beam is wider than the diameter of the workpiece being processed.

Over the years, ion implanters have become very sophisticated tools incorporating the use of energy filters, collimators, scanning systems and more recently molecular ion sources, cryogenic and elevated implant temperature capabilities. As memory and logic architectures continue to expand and complex structures such as gate-all-around become possible, the need to control and modify near surface processes following ion implantation. Is increasing. These surface proximal processes include native oxide cleaning, surface passivation, new damage engineering techniques to reduce defects, staged profiles from surface to typical retrograde profiles of the beamline, and ion. The beam itself may comprise selective processing, which is a catalyst for reactions on the surface.

Thus, it would be beneficial if there was a semiconductor processing system and method for creating an inline surface engineering source in proximity to a work piece to perform surface proximal processes on the work piece with an ion beam.

A system is disclosed having an auxiliary plasma source disposed proximate a workpiece for use with an ion beam. The auxiliary plasma source is used to generate ions and radicals that can drift towards the workpiece and form a film. The ion beam is then used to provide energy so that the ions and radicals can process the workpiece. Additionally, various applications of the system are disclosed. For example, the system can be used for a variety of processes including deposition, implantation, etching, pre-treatment and post-treatment. By placing the auxiliary plasma source close to the work piece, processes that were not previously possible can be performed. Additionally, two dissimilar processes such as cleaning and injection or injection and passivating can be performed without removing the workpiece from the end station.

According to one embodiment, a semiconductor processing system is disclosed. A semiconductor processing system includes an ion source for generating an ion beam; And an auxiliary plasma source disposed proximate the work piece, the auxiliary plasma source having an outlet opening oriented to emit ions and radicals toward the work piece. In some embodiments, the ion source is a component of the beamline ion system. In certain embodiments, the auxiliary plasma source includes an outer housing, an antenna disposed within the outer housing, and an RF power supply in communication with the antenna. In other embodiments, the auxiliary plasma source includes an outer housing, an antenna disposed outside the outer housing and proximate a wall of the outer housing, and an RF power supply in communication with the antenna. In certain embodiments, the outlet opening is oriented such that radicals and ions are directed toward the workpiece at a location where the ion beam impinges on the workpiece. In other embodiments, the outlet opening is oriented such that radicals and ions are directed toward the workpiece in a direction parallel to the ion beam. In certain embodiments, the auxiliary plasma source is biased to attract ions to the workpiece. In some embodiments, the system includes an end station within which the work piece is disposed, wherein the auxiliary plasma source is disposed within the end station. In some embodiments, a heater is disposed within the end station. In certain embodiments, a plasma flood gun separate from the auxiliary plasma source is disposed within the end station.

According to another embodiment, a method of implanting ions of a desired species into a workpiece is disclosed. The method comprises generating a plasma in an auxiliary plasma source using a gas containing the desired species, wherein the auxiliary plasma source is positioned close to the workpiece, and ions and radicals from the plasma exit the auxiliary plasma source. Moving toward me and the work piece; And using an ion beam generated using an ion source different from the auxiliary plasma source, knocking ions and radicals from the auxiliary plasma source into the workpiece. In some embodiments, the ion beam comprises an inactive species. In certain embodiments, ions and radicals from the plasma are directed toward the workpiece at a location where the ion beam strikes the workpiece. In some embodiments, the ions and radicals form a film on the surface of the work piece at a location where the ion beam strikes the work piece. In certain embodiments, a desired species includes molecules comprising a Group III, IV or V group element.

According to another embodiment, a method of processing a workpiece is disclosed. The method comprises generating a plasma in an auxiliary plasma source using a gas comprising an etching species, wherein the auxiliary plasma source is located in close proximity to the workpiece in the end station, and ions and radicals from the plasma are Exiting the source and reacting with the native oxide layer on the surface of the workpiece; Heating the workpiece after the reaction, the heat causing sublimation of the native oxide layer on the workpiece; And performing an additional process on the work piece using an ion beam generated using an ion source different from the auxiliary plasma source, the work piece remaining in the end station. In certain embodiments, the etch species is selected from the group consisting of ammonia and NF ₃ . In some embodiments, the workpiece is scanned such that a portion of the workpiece is exposed to plasma and then to heat. In some embodiments, the steps of creating and heating are repeated until the surface of the workpiece is cleaned.

According to another embodiment, a method of etching a workpiece is disclosed. The method comprises the steps of generating a plasma in an auxiliary plasma source using a gas comprising an etching species, wherein the auxiliary plasma source is positioned close to the work piece, and ions and radicals from the plasma are directed towards a portion of the work piece. Exiting the auxiliary plasma source and forming a film on a portion of the workpiece; And using an ion beam generated using an ion source different from the auxiliary plasma source to provide energy to etch the workpiece. In certain embodiments, the etch species comprises halogen. In some embodiments, the etch species comprises CF ₄ and oxygen. In certain embodiments, the etch species comprises halogen and the autogenous oxide layer is etched. In some embodiments, the ion beam comprises an inert gas. In certain embodiments, the ion beam is directed to a portion of the work piece while the film is being created. In certain embodiments, the ion beam is sent to the part of the work piece after the film is created.

According to another embodiment, a method of depositing a material on a workpiece is disclosed. The method comprises the steps of creating a plasma in an auxiliary plasma source using a process gas, wherein the auxiliary plasma source is positioned proximate a workpiece, and ions and radicals from the plasma direct the auxiliary plasma source towards a portion of the workpiece. Exiting and forming a film on a portion of the work piece; And using an ion beam generated using an ion source different from the auxiliary plasma source to provide energy for depositing the material on the workpiece. In certain embodiments, the process gas comprises CH ₄ and the ion beam comprises a Group IV element. In some embodiments, a more boxed profile is created than that produced using only the ion beam.

According to another embodiment, a method of processing a workpiece is disclosed. The method includes sending ions toward a workpiece using an ion beam; A step of generating a plasma in an auxiliary plasma source using a process gas, wherein the auxiliary plasma source is located in close proximity to the work piece in the end station, and ions and radicals from the plasma exit the auxiliary plasma source and Reacting with; And heating the workpiece after the reaction, wherein the heat repairs damage caused by the ion beam on the surface of the workpiece. In certain embodiments, an ion beam is used to implant ions into the workpiece. In certain embodiments, the workpiece is scanned such that a portion of the workpiece is exposed to plasma and then to heat. In some embodiments, the workpiece is heated to a temperature between 100° and 500°C. In certain embodiments, the process gas comprises a hydrogen/nitrogen mixture. In some embodiments, the entire work piece is processed by the ion beam prior to the generating and heating steps. In certain embodiments, a portion of the workpiece is processed by an ion beam while a second portion is reacted with the plasma.

For a better understanding of the present disclosure, reference is made to the accompanying drawings, which are incorporated herein by reference.
1 is a representative diagram of a beam-line implantation system for generating a ribbon ion beam that can be used with an in-line surface engineering source according to one embodiment.
2 shows the end station of FIG. 1 according to an embodiment.
3A illustrates the auxiliary plasma source of FIG. 2 according to an embodiment.
3B illustrates the auxiliary plasma source of FIG. 2 according to another embodiment.
4A is a block diagram of the end station of FIG. 2 according to an embodiment.
4B is a block diagram of the end station of FIG. 2 according to another embodiment.
Figure 5 shows an ion implantation using the end station of Figure 4a.
6 shows a representative flow diagram of a pre-processing process.
7 shows a representative flow chart of one post-processing process.
8 illustrates a semiconductor processing system using an inline surface engineering source according to another embodiment.

1 shows a beamline ion implantation system that may be used with an inline surface engineering source according to one embodiment. A beam line ion implantation system can be used to process a workpiece using a ribbon ion beam.

The beamline ion implantation system includes an ion source 100 comprising a plurality of chamber walls defining an ion source chamber. In certain embodiments, the ion source 100 may be an RF ion source. In this embodiment, the RF antenna can be placed against the dielectric window. Such a dielectric window may comprise part or all of one of the chamber walls. The RF antenna may comprise an electrically conductive material such as copper. The RF power supply is in electrical communication with the RF antenna. The RF power supply can supply RF voltage to the RF antenna. The power supplied by the RF power supply can be between 0.1 and 10 kW, and can be any suitable frequency such as between 1 and 100 MHz. Additionally, the power supplied by the RF power supply can be pulsed.

In another embodiment, a cathode is disposed within the ion source chamber. The filament is placed behind the cathode and energized to emit electrons. These electrons are attracted to the cathode, which in turn releases electrons into the ion source chamber. Since the cathode is heated indirectly by electrons emitted from the filament, this cathode may be referred to as an indirectly heated cathode (IHC).

Other embodiments are also possible. For example, the plasma is in different ways, such as by a Bernas ion source, a capacitively coupled plasma (CCP) source, a microwave or an ECR (electron-cyclotron-resonance) ion source. Can be created. The manner in which the plasma is generated is not limited by the present disclosure.

One chamber wall, referred to as an extraction plate, contains an extraction opening. The extraction opening may be an opening through which ions 1 generated in the ion source chamber are extracted and sent toward the work 10. Workpiece 10 may be a silicon wafer, or may be another substrate suitable for semiconductor fabrication such as GaAs, GaN or GaP. The extraction opening can be of any suitable shape. In certain embodiments, the extraction opening may be oval or rectangular in shape with one dimension referred to as width (x-dimension), which may be much larger than a second dimension referred to as height (y-dimension). .

The extraction optics 110 are disposed outside and close to the extraction opening of the ion source 100. In certain embodiments, the extraction optics 110 includes one or more electrodes. Each electrode can be a single electrically conductive component with an opening disposed therein. Alternatively, each electrode may consist of two electrically conductive components spaced apart to create an opening between the two components. The electrodes can be a metal such as tungsten, molybdenum or titanium. One or more of the electrodes may be electrically connected to ground. In certain embodiments, one or more of the electrodes may be biased using an electrode power supply. The electrode power supply may be used to bias one or more of the electrodes to the ion source to attract ions through the extraction opening. The extraction opening and the opening in the extraction optic are aligned so that the ions 1 pass through both of the openings.

The first quadrupole lens 120 is located downstream from the extraction optical unit 110. The first quadrupole lens 120 cooperates with other quadrupole lenses in the system to focus the ions 1 into the ion beam.

The mass spectrometer 130 is located downstream from the first quadrupole lens 120. The mass spectrometer 130 uses a magnetic field to guide the path of the extracted ions 1. The magnetic field affects the flight path of ions depending on their mass and charge. A mass decomposition device 150 having a resolving opening 151 is disposed at the output of the mass spectrometer 130, or at the distal end. With the proper selection of the magnetic field, only these ions 1 of the selected mass and charge will be sent through the decomposition opening 151. Other ions will impinge on the walls of the mass resolution device 150 or the mass spectrometer 130 and will not move further within the system.

The second quadrupole lens 140 may be disposed between the output of the mass analyzer 130 and the mass decomposition device 150.

The collimator 180 is disposed downstream from the mass decomposition device 150. The collimator 180 receives ions 1 passing through the decomposition opening 151 and generates a ribbon ion beam formed of a plurality of parallel or nearly parallel beamlets. The output or distal end of mass spectrometer 130 and the input or proximal end of collimator 180 may be spaced a fixed distance. The mass decomposition device 150 is disposed within the space between these two components.

The third quadrupole lens 160 may be disposed between the mass decomposition device 150 and the input of the collimator 180. A fourth quadrupole lens 170 may also be disposed between the mass decomposition device 150 and the input of the collimator 180.

In certain embodiments, the quadrupole lenses may be placed in different positions. For example, the third quadrupole lens 160 may be disposed between the second quadrupole lens 140 and the mass decomposition device 150. Additionally, in certain embodiments, one or more of the quadrupole lenses may be omitted.

The acceleration/deceleration stage 190 may be located downstream from the collimator 180. The acceleration/deceleration stage 190 may be referred to as an energy purity module. The energy purity module is a beam-line lens component configured to independently control deflection, deceleration, and focusing of an ion beam. For example, the energy purity module may be a vertical electrostatic energy filter (VEEF) or an electrostatic filter (EF).

The ions 1 exit the acceleration/deceleration stage 190 as an ion beam 191 and enter the end station 200. The ion beam 191 may be a ribbon ion beam. The workpiece 10 is placed within the end station 200.

Thus, the beamline ion implantation system includes a plurality of components that terminate at the end station 200. As described above, these components include: an ion source 100; Extraction optics 110; Quadrupole lenses 120, 140, 160, 170; Mass spectrometer 130; Mass decomposition device 150; Collimator 180; And an acceleration/deceleration stage 190. It should be noted that one or more of these components may not be included within the beamline ion implantation system.

Additionally, although the above disclosure describes a ribbon ion beam having a width much greater than its height, other embodiments are also possible. For example, a scan-type spot beam may enter the end station 200. The scan-type spot beam is an ion beam that is typically in the shape of a circle, which is scanned laterally to produce the same effect as a ribbon ion beam.

The controller 195 can be used to control the system. Controller 195 has a processing unit and an associated memory device. Such a memory device contains instructions that, when executed by the processing unit, enable the system to perform the functions described herein. Such a memory device may be any non-transitory storage medium including non-volatile memory, such as flash ROM, electrically erasable ROM or other suitable devices. In other embodiments, the memory device may be a volatile memory such as RAM or DRAM. In certain embodiments, the controller 195 may be a general purpose computer, an embedded processor, or a specially designed microcontroller. The actual implementation of the controller 195 is not limited by this disclosure.

2 shows an end station 200 according to an embodiment. As described above, the workpiece 10 is placed within the end station 200. An ion beam 191 enters the end station 200 and is directed towards the workpiece 10. The workpiece 10 is held by the platen 210. The platen 210 may rotate about an axis perpendicular to the front surface of the platen 210. Platen 210 can also rotate about an axis 211 parallel to the front surface of platen 210. Additionally, platen 210 may move linearly along direction 212. Of course, platen 210 may also have less than all of these capabilities.

A plasma flood gun 220 may be placed within the end station 200 and in proximity to the ion beam 191. The plasma flood gun 220 is used to emit low energy electrons to reduce space charge blowup and to neutralize the workpiece 10. In particular, the plasma flood gun 220 is purely negative in the form of electrons from a plasma formed of a rare gas or a non-reactive gas rather than another plasma species such as atoms or molecular radicals from molecular dissociation. It is only used to emit negatively charged flux. In other words, the plasma flood gun 220 uses an inert gas, such as xenon, to emit electrons. The plasma flood gun 220 is not intended to change the properties of the workpiece 10.

In one embodiment, the plasma flood gun 220 may include a plasma chamber 221 having a substantially metal-free inner surface. A radio-frequency coil 222 may be placed within the plasma chamber 221 to directly excite the gas enclosed in the chamber and thus generate and maintain the desired plasma. The plasma chamber 221 may have an elongated extraction opening 223 on one side thereof through which plasma flows out of the plasma chamber 221 and meshes with ions of the ion beam 191. A series of magnets 224 may be placed around the plasma chamber 221 to contain and control the plasma generated therein. In particular, the magnets 224 may be located outside the walls of the plasma chamber 221 and their respective magnetic fields extend through the walls of the plasma chamber 221.

More specifically, the inner parts of the plasma chamber 221 may be made of a non-metallic conductive material such as graphite or silicon carbide (SiC). A feed-through gas pipe may be provided in the sidewall of the plasma chamber 221, through which one or more gaseous substances may be supplied to the plasma chamber 221. The gaseous substances may include inert gases such as xenon (Xe), argon (Ar) or krypton (Kr). The gas pressure is typically maintained in the range of 1-50 mTorr.

The radio-frequency coil 222 may generally have an elongated shape extending through the center of the plasma chamber 221. One end of the radio-frequency coil 222 may be connected to an RF power supply capable of inductively coupling RF power within the plasma chamber 221. RF power can operate at typical frequencies such as 2 MHz, 13.56 MHz and 27.12 MHz, for example. The radio-frequency coil 222 may be completely enclosed within the plasma chamber 221. In the sidewall of the plasma chamber, an outlet opening 223 is positioned to allow the generated plasma to flow in contact with the ion beam 191. For a ribbon-shaped ion beam, the exit opening 223 can substantially cover the ribbon width.

According to an embodiment, it may be desirable to form a plasma bridge with the ion beam 191 through which plasma from the plasma flood gun 220 passes directly outside the plasma chamber 221. As mentioned above, the plasma chamber 221 may include a series of magnets 224 such as permanent magnets or electromagnets arranged to contain and control the plasma generated in the plasma chamber 221 . The properties of these magnets 224 can also be arranged to control the properties of the plasma as it exits the plasma chamber 221 through the outlet opening 223.

In other embodiments, the plasma flood gun 220 may be a Bernas type of ion source, where filaments are used to generate thermionic emission. A gas such as argon is introduced into the plasma chamber. The emitted electrons are used to excite the plasma in the plasma chamber. Then, electrons from the plasma are extracted from the plasma chamber through the outlet opening.

In other words, the plasma flood gun 220 can be configured in various ways, and its implementation is not limited by the present disclosure.

Thus, electrons from the plasma flood gun 220 can be confined by the magnetic field to direct their path towards the ion beam 191. In certain embodiments, the plasma flood gun 220 may not be used.

The auxiliary plasma source 270 is disposed within the end station 200. Unlike plasma flood gun 220, auxiliary plasma source 270 is used to emit ions and/or radicals through one or more outlet openings 275 into an area proximate to workpiece 10. As is well known, radicals are molecules or atomic species with unpaired valence electrons. As a result, radicals are typically highly reactive. Radicals are typically generated by the dissociation of larger molecules within the auxiliary plasma source 270. In certain embodiments, the auxiliary plasma source 270 is disposed within 30 cm of the workpiece 10, although other embodiments are possible. While the auxiliary plasma source 270 is illustrated as a cylindrical shape, it will be appreciated that this is only exemplary and that the auxiliary plasma source 270 may be of any shape.

In certain embodiments, heater 240 may also be disposed within end station 200. The heater 240 may be located near the auxiliary plasma source 270, so that both the heater 240 and the auxiliary plasma source 270 are disposed on the same side of the ion beam 191. The heater 240 can be any suitable device, including heating lamps, LEDs, or resistive heaters. 2 shows an auxiliary plasma source 270 disposed between the ion beam 191 and the heater 240, but other configurations are also possible. For example, the heater 240 may be disposed between the ion beam 191 and the auxiliary plasma source 270. In another embodiment, the heater 240 and the auxiliary plasma source 270 may be disposed on opposite sides of the ion beam 191.

In the embodiment shown in Fig. 3A, the auxiliary plasma source 270 includes an outer housing 231, which may be cylindrical, although other shapes are also possible. The outer housing 231 may be constructed of aluminum or any other suitable material. An antenna 232 is present in the outer housing 231, which may be surrounded by a protective cover 233. The antenna 232 may be made of a conductive material such as metal, and may be U-shaped. The antenna 232 is coated with a protective cover 233, which may be a ceramic material to protect the antenna 232 from plasma 274 generated within the auxiliary plasma source 270, or is coaxial therein. The outer housing 231 includes one or more outlet openings 275 through which the plasma 274 exits the auxiliary plasma source 270 and enters the end station 200. In operation, the process gas is introduced into the volume defined by the outer housing 231. The antenna 232 is energized using an RF power source 235. This energy creates a plasma 274 in the auxiliary plasma source 270. The plasma 274 then exits the auxiliary plasma source 270 through one or more outlet openings 275.

3B shows an auxiliary plasma source 270 according to another embodiment. In this embodiment, the auxiliary plasma source 270 has an antenna 252 disposed outside the outer housing 251. The antenna 252 is energized using an RF power supply 255. For example, a wall proximate to antenna 252 may be a dielectric material such that energy from antenna 252 passes through the wall and into a volume defined by outer housing 251. Process gas is introduced into this volume, and when energy is supplied, it creates a plasma 274. The plasma 274 then exits the auxiliary plasma source 270 through one or more outlet openings 275.

Other types of devices may be used for the auxiliary plasma source 270. For example, an indirectly heated cathode (IHC) ion source may be used. Alternatively, a Bernas source can be used. In other embodiments, an inductively coupled plasma (ICP) or capacitively coupled plasma (CCP) source may be used. Accordingly, the auxiliary plasma source 270 is not limited to those shown in FIGS. 3A to 3B.

In certain embodiments, such as the one shown in FIG. 4A, the auxiliary plasma source 270 has one or more outlet openings 275 at a location where the ion beam 191 strikes the workpiece 10. It can be oriented to emit plasma 274 towards (10). In this way, the ion beam 191 cooperates with the plasma 274 to process the workpiece 10. For example, ions and radicals in the plasma 274 may be deposited on the workpiece 10 in a region exposed to the ion beam 191. As described with respect to FIG. 2, the end station 200 may include a plasma flood gun 220 and/or a heater 240, if desired.

4B shows an end station 200 according to another embodiment. In this embodiment, the auxiliary plasma source 270 is oriented such that the one or more outlet openings 275 are directly facing the workpiece 10. In this way, the flow of plasma 274 is parallel to the ion beam 191. As described with respect to FIG. 2, the end station 200 may include a plasma flood gun 220 and/or a heater 240, if desired.

In the embodiments shown in FIGS. 4A-4B, a process gas may be introduced into the auxiliary plasma source 270. The antenna is energized, for example through the use of an RF power supply. The energy in the antenna causes the process gas in the auxiliary plasma source 270 to ionize to form a plasma 274. Then, this plasma 274 exits toward the workpiece 10 through one or more outlet openings 275. In certain embodiments, a voltage difference may exist between the auxiliary plasma source 270 and the workpiece 10. For example, the auxiliary plasma source 270 may be biased more positively than the work piece 10. In some embodiments, auxiliary plasma source 270 may be biased 0-5000V more positively than workpiece 10. In certain embodiments, the auxiliary plasma source 270 may be biased more positively than the workpiece 10 by between 0-500V. In this embodiment, positive ions in the auxiliary plasma source 270 are accelerated toward the workpiece 10. Alternatively, the auxiliary plasma source 270 can be biased more negatively than the workpiece 10. In this embodiment, the positive ions in the auxiliary plasma source 270 are reflected to some extent by the workpiece 10. In other embodiments, the auxiliary plasma source 270 is at the same potential as the workpiece 10 so that the ion and radical flux from the auxiliary plasma source 270 simply drifts through the one or more outlet openings 275. I can.

In the embodiment shown in FIG. 4A, as the platen 210 moves upward along the direction 212, a portion of the workpiece 10 is removed from the ion beam 191 and the auxiliary plasma source 270. Is exposed to the plasma 274 of the. After this exposure, that portion of the workpiece 10 can then be heated by the heater 240.

In the embodiment shown in FIG. 4B, the workpiece 10 is first processed by the ion beam 191 and then by the plasma 274 as it moves upward. After exposure to the ion beam 191 and the plasma 274, the workpiece 10 may then undergo a thermal process by the heater 240.

The use of heat following treatment with ion beam 191 and/or plasma 274 can have beneficial applications.

It should be noted that any type of auxiliary plasma source may be used in the configurations shown in FIGS. 4A-4B. Thus, the choice of the type of auxiliary plasma source 270 and its orientation are design decisions based on the process being performed and other considerations.

The energy applied by the antenna as well as the flow rate of the process gas into the auxiliary plasma source 270 are factors that determine the number of radicals and ions extracted from the auxiliary plasma source 270. In certain embodiments, the process gas is diluted with an inert gas to maintain the plasma or to reduce the number of radicals and ions of a desired species for process control.

While FIG. 1 is described in connection with ion implantation, it will be appreciated that end station 200 may be used with any semiconductor processing system. With the described semiconductor processing system having a source engineering source, various applications of such a semiconductor processing system will be described.

In one embodiment, the semiconductor processing system of FIG. 1 using the configuration shown in FIG. 4A may be used to perform the ion implantation process. As described above, the end station of FIG. 4A transmits the plasma 274 from the auxiliary plasma source 270 toward the workpiece 10 at a position where the ion beam 191 collides with the workpiece 10. Describe. In this way, there is a simultaneous interaction between the plasma 274 and the ion beam 191 with the surface of the workpiece 10.

In this embodiment, it is desired to be injected into the target paper work 10. For example, the target species may be a group III element, an IV element, or a group V element. For example, in one embodiment, arsenic may be the desired species. This desired species is introduced into the auxiliary plasma source 270. The desired species can be introduced in the form of a molecule comprising the target species. Energy is supplied to this desired species to form plasma 274. As shown in FIG. 5, the plasma 274 diffuses toward the workpiece 10 near the position where the ion beam 191 strikes the workpiece 10. Ions and radicals from the plasma 274 may be deposited on the surface of the workpiece 10, for example in the form of a film 277. A gas such as argon, xenon or krypton is introduced into the ion source 100 (FIG. 1) and used to generate the ion beam 191. In certain embodiments, the gas may be an inert species defined as a Group VIII element such as neon, argon, xenon, or krypton. The ion beam 191 collides with ions and radicals from the plasma 274 deposited on the workpiece 10 as a film 277 or in proximity to the workpiece. These collisions transfer a large portion of the energy from the ions in the ion beam 191 to the ions and radicals from the plasma 274. This allows the ions and radicals from the plasma 274 to acquire the required speed to penetrate the surface of the workpiece 10. Thus, the energy of the ions in the ion beam 191 is imparted to the ions and radicals from the plasma 274. This allows ions and radicals in the film 277 to be driven into the workpiece 10. In this embodiment, ion beam 191 is used to strike ions and radicals from plasma 274. Thus, unlike conventional ion implanters, the ions in the ion source 100 are used to provide energy to drive into the ions and radicals generated in the auxiliary plasma source 270 in the end station 200. .

Thus, in this embodiment, the ion beam 191 is used to provide energy, while the auxiliary plasma source 270 is used to supply the desired species. Although the above description uses inert gases and arsenic, these are completely exemplary and the present disclosure is not limited to these embodiments. The ion beam 191 can be made of ions of any species. In some embodiments, certain species, such as inert elements or group IV elements, may be used so that the ion beam does not affect the conductivity of the silicon wafer. The target species may be any desired species, including Group III elements such as boron and gallium, and Group V elements such as phosphorus and arsenic. In certain embodiments, Group III elements and Group V elements may be combined with other elements to form molecules such as BF ₃ , AsH ₃ , PH ₃ , and others.

In another embodiment, the semiconductor processing systems described herein can be used for an etching process. In particular, the use of an auxiliary plasma source 270 allows the generation of more chemically active radicals near the work piece. In this case, the auxiliary plasma source 270 is used to generate ions, radicals, and metastable neutral particles of the etching chemistry, such as Group VII elements and molecules containing these elements. These ions and metastable neutral particles exit the auxiliary plasma source 270 and drift toward the workpiece 10. Because the ions from the auxiliary plasma source 270 have low energy, these ions deposit on or near the surface of the workpiece 10.

In one specific embodiment, a halogen containing gas is introduced into the auxiliary plasma source 270 to generate ions. Low energy ions and radicals exiting the auxiliary plasma source 270 may form a thin film on the surface of the work 10. This thin film reacts with the workpiece 10 to etch the workpiece with the energy provided by the ion beam 191. In certain embodiments, the ion beam 191 may include an inert gas such as argon. In one embodiment, the embodiment of FIG. 4A is used to direct an ion beam 191 towards a portion of the workpiece 10 while the film is being formed. In another embodiment, the embodiment of FIG. 4B is used to direct the ion beam 191 towards a portion of the workpiece 10 after the film is formed.

In another specific embodiment, CF ₄ and oxygen are ionized and dissociated within the auxiliary plasma source 270. An ion beam 191 composed of an inert gas such as argon is used to etch the surface of the workpiece 10.

In another specific embodiment, an autogenous oxide layer may be formed on the surface of the workpiece 10. Such an autogenous oxide layer may be etched by ionizing hydrogen in the auxiliary plasma source 270. An ion beam composed of an inert gas such as argon is used to etch the native oxide from the surface of the work piece 10.

In another embodiment, the semiconductor processing system of FIGS. 1-4 may be used for deposition. The material to be deposited may be ionized within the auxiliary plasma source 270. The material may be a dopant or may be a material used as a coating for the workpiece 10. Ions and radicals from the material exit the auxiliary plasma source 270 and drift towards the workpiece 10, where they are deposited on the surface of the workpiece 10.

In one particular embodiment, the process gas may be CH ₄ , while the ion beam 191 contains a Group IV element such as carbon. This enables a more box-shaped profile within the workpiece 10. In contrast, the use of ion beam 191 alone creates a retrograde profile.

Thus, in applications where the ion beam 191 and the auxiliary plasma source 270 are used at the same time, the ion beam 191 may be used to perform at least one of the two functions.

First, the ion beam 191 can supply the energy required to drive ions and radicals from the auxiliary plasma source 270 towards and into the workpiece 10. One example of this is the use of an ion beam 191 to strike ions from the plasma 274 into the workpiece 10, as shown in FIG. 5.

Second, the ion beam 191 can supply additional species to facilitate or cause chemical reactions at the surface of the workpiece 10. This can be accomplished in a number of ways. First, the ion beam 191 may weaken the bonds of the work 10 below so that the surface of the work 10 reacts with the deposited layer. Second, the ion beam 191 can mix the deposited layer into the workpiece 10 below for more reactions. Third, the ion beam 191 may release or volatilize a newly formed compound formed from the work 10 and the deposited layer. The sputtering yield of these newly formed compounds may be much higher than the sputtering yield of single use of the ion beam 191 for the workpiece 10. For example, in the etching process, CF ₄ and oxygen radicals create a CF _x polymer type material with silicon nitride on the surface of the workpiece 10. The resulting SiF _x C _y compound is volatilized by the energy of the ion beam 191.

In another embodiment, the use of the auxiliary plasma source 270 and the ion beam 191 may not be simultaneous. For example, the workpiece 10 may be processed by one of these sources, and then processed by another of these sources at a later time.

For example, in one embodiment, an auxiliary plasma source is used to provide pre-treatment of the workpiece 10. A flowchart of this process is shown in FIG. 6. In this embodiment, since the ion beam 191 is not active during pre-treatment, the embodiment of Fig. 4A or 4B can be used. First, as shown in process 500, ion beam 191 is disabled. One or more etch papers, such as ammonia (NH ₃ ) and NF ₃ , are introduced into the auxiliary plasma source 270, as shown in process 510. The auxiliary plasma source 270 generates ions and other radicals. As shown in process 520, ions and radicals exit auxiliary plasma source 270 and drift towards workpiece 10, where they react with the silicon oxide layer of workpiece 10. Work piece 10 is then scanned so that the portion of work piece 10 that has been exposed to ions and radicals is heated by heater 240, as shown in process 530. The heat serves to sublimate the reacted silicon oxide generated on the surface of the workpiece 10, as shown in process 540. This process is repeated until the surface of the workpiece 10 is cleaned. Thereafter, the workpiece 10 may undergo another process with an ion beam 191, as shown in process 550. Advantageously, the workpiece 10 remains within the end station 200 throughout the pre-processing and second process shown in the process 550. In other words, the workpiece 10 does not leave the end station between the pre-processing and the second process.

In another embodiment, the process described above may be performed when the work piece 10 is not disposed on the platen 210. In this embodiment, this process may serve to clean the platen 210.

In another embodiment, the auxiliary plasma source 270 is used in post-processing of the workpiece 10. For example, post-treatment may be used to passivate the surface of the workpiece 10 or to repair damage caused by the ion implantation process. Its flow chart is shown in FIG. 7. First, as described above, the workpiece 10 is processed using an ion beam 191. Then, as shown in process 610, a process gas is introduced into the auxiliary plasma source 270. The process gas may comprise a hydrogen/nitrogen mixture. As shown in process 620, ions and radicals from auxiliary plasma source 270 are directed towards the surface of workpiece 10. Work piece 10 is scanned past heater 240, for example at a temperature of 100°C-500°C, as shown in process 630. Damage repair has been shown to work with forming gases at reduced temperatures, referred to as plasma annealing. Passivation occurs by reacting radicals of hydrogen or nitrogen with dangling bonds on the surface, as shown in process 640.

In one embodiment, the post-processing shown in FIG. 7 is performed while the ion beam 191 is disabled. In another embodiment, the post-processing can be performed using the embodiment shown in FIG. 4B. In particular, the workpiece 10 is implanted by the ion beam 191. As the workpiece 10 is moved upward in the direction 212, the injected portion is then exposed to the process gas from the auxiliary plasma source 270. After that, the implanted part is then heated. Thus, in this embodiment, the workpiece 10 is implanted and post-processed by the ion beam 191 during a single scan of the workpiece 10. In other words, while one part of the work piece is exposed to the ion beam, a second part of the work piece different from the first part is exposed to the plasma.

Thus, the present disclosure describes a semiconductor processing system in which a source of ions and radicals is incorporated within the end station 200. Conventionally, great efforts have been made to ensure that no ions or radicals are introduced into the end station 200. In particular, the plasma flood gun 220 is designed to ensure that most of the electrons are released into the end station 200. The present semiconductor processing system intentionally introduces ions and radicals into the end station 200. In certain embodiments, these ions and radicals are introduced concurrently with the use of the ion beam 191 to perform applications that would otherwise not have been possible.

While the above disclosure describes the use of the auxiliary plasma source 270 with a beamline ion implanter system, other embodiments are also possible. For example, Fig. 8 shows this example. In this figure, the semiconductor processing system includes an ion source chamber 700 composed of a plurality of chamber walls 701. In certain embodiments, one or more of these chamber walls 701 may be made of a dielectric material such as quartz. The RF antenna 710 may be disposed on the outer surface of the first dielectric wall 702. The RF antenna 710 may be powered by an RF power supply device 720. Energy delivered to the RF antenna 710 is radiated in the ion source chamber 700 to ionize the supply gas introduced through the gas injection port 730. In other embodiments, the gas may be in different ways, e.g. the use of an indirectly heated cathode (IHC), a capacitively coupled plasma source, an inductively coupled plasma source, a Bernas source or any other plasma generator. Is ionized through.

One chamber wall, referred to as extraction plate 740, includes an extraction opening 745 through which ions can exit the ion source chamber 700. The extraction plate 740 may be made of an electrically conductive material such as titanium, tantalum or other metal. The extraction plate 740 may have a width exceeding 300 millimeters. Additionally, the extraction plate 745 may be wider than the diameter of the workpiece 10. In certain embodiments, the extraction optics 750, such as an electrode, may be disposed outside the extraction opening 745 to accelerate the ions generated in the ion source chamber 700 toward the workpiece 10. have.

The platen 760 is disposed outside the ion source chamber 700 near the extraction opening 745. Work piece 10 is placed on platen 760.

The auxiliary plasma source 270 may be as described with respect to FIG. 3A in certain embodiments. In other embodiments, the auxiliary plasma source 270 may be as described with respect to FIG. 3B. Additionally, the outlet openings 275 of the auxiliary plasma source 270 may be oriented as shown in FIG. 4A or 4B.

In certain embodiments, the plasma flood gun 220 may not be used. The plasma flood gun 220 functions as described above.

All of the processes described herein can be performed using the configuration shown in FIG. 8.

The semiconductor processing systems and methods described herein can have a number of advantages.

In the case of implementations using knock in, the depth of the injection can be tighter controlled. Additionally, when a molecule such as AsH ₃ is implanted, the depth of hydrogen ions can be better controlled using knock-in. There are additional advantages associated with the use of knock-in. First, the stragle from the implanted ions can be reduced due to the deposited film absorbing energy. This is beneficial for applications such as source/drain extensions where lateral strangles can cause short channel effects under the gate. Second, the resulting dopant profile will be a surface peak, which will produce a surface peak carrier concentration. This is beneficial for applications such as contacts where a close surface is consumed by the silicide process and low contact resistance in this area is desired. Third, the doping of the sidewalls of the fins may be improved by sputtering the film on which impending ions are deposited to adjacent fin structures.

In the case of etching, the use of an auxiliary plasma source 270 allows removal of the native oxide layer within the same end station when a subsequent process is performed therein. An additional advantage of this configuration in etching and deposition applications is the ability to process or produce thicker films while maintaining low energy by a sequential process. Low energy may be useful to prevent unwanted sputtering or damage of the underlying layers.

In the case of sequential operation, the use of an auxiliary plasma source 270 in the end station eliminates the need to transport the workpiece after the pre-treatment cleaning process. It also reduces the amount of time between cleaning and processing (ie, deposition, implantation, etching). For example, if the application is sensitive to autogenous oxide layers, the reduction of the time between cleaning the surface of the work piece and the work piece undergoing the desired process minimizes regrowth of the autogenous oxide layer.

The present disclosure is not limited in scope by the specific embodiments described herein. Rather, in addition to the embodiments described herein, other various embodiments of the present disclosure and modifications thereto will become apparent to those skilled in the art from the above description and accompanying drawings. Accordingly, these other embodiments and modifications are intended to be within the scope of this disclosure. Additionally, although the present disclosure has been described herein in the context of a particular embodiment in a particular environment for a particular purpose, those skilled in the art are not limited in its usefulness, and the present disclosure is intended to be used in any number of environments for any number of purposes. It will be appreciated that it can be beneficially implemented in. Accordingly, the claims set forth below should be interpreted in light of the full breadth and spirit of the present disclosure as described herein.

Claims (35)

As a semiconductor processing system,
An ion source for generating ions used to form the ion beam; And
And an auxiliary plasma source disposed proximate the work piece, the auxiliary plasma source having an outlet opening oriented to emit ions and radicals toward the work piece.
The method according to claim 1,
Wherein the ion source is a component of a beamline ion system.
The method according to claim 1,
The auxiliary plasma source includes an outer housing, an antenna, and an RF power supply in communication with the antenna.
The method according to claim 1,
Wherein the exit opening is oriented to direct the radicals and ions towards the workpiece at a location where the ion beam impinges on the workpiece.
The method according to claim 1,
Wherein the exit opening is oriented such that the radicals and ions are directed toward the workpiece in a direction parallel to the ion beam.
The method according to claim 1,
Wherein the auxiliary plasma source is biased such that the ions are attracted to the workpiece.
The method according to claim 1,
Wherein the semiconductor processing system includes an end station to which a workpiece is disposed, and the auxiliary plasma source is disposed within the end station.
The method of claim 7,
Wherein the semiconductor processing system includes a heater disposed within the end station.
The method of claim 7,
Wherein the semiconductor processing system includes a plasma flood gun disposed within the end station and separate from the auxiliary plasma source.
As a method of implanting ions of a desired species into the work piece,
Generating a plasma in an auxiliary plasma source using a gas containing the desired species, wherein the auxiliary plasma source is located close to the work, and ions and radicals from the plasma are the auxiliary plasma source Exiting and moving toward the work piece; And
And knocking the ions and radicals from the auxiliary plasma source into the workpiece using an ion beam generated using a different ion source than the auxiliary plasma source.
The method of claim 10,
The method of claim 1, wherein the ion beam comprises an inactive species.
The method of claim 10,
The ions and radicals from the plasma are directed toward the workpiece at a location where the ion beam impinges on the workpiece.
The method of claim 12,
The method, wherein the ions and radicals form a film on the surface of the work piece at a location where the ion beam strikes the work piece.
The method of claim 10,
Wherein the desired species comprises a molecule comprising a Group III, IV or V group element.
As a method of processing a work,
Generating a plasma in an auxiliary plasma source using a gas containing an etching species, wherein the auxiliary plasma source is located in close proximity to the workpiece in an end station, and ions and radicals from the plasma are Exiting the plasma source and reacting with the native oxide layer on the surface of the workpiece;
Heating the workpiece after the reaction, wherein heat causes sublimation of the native oxide layer on the workpiece; And
Performing an additional process on the work piece using an ion beam generated using an ion source different from the auxiliary plasma source, the work piece remaining within the end station.
The method of claim 15,
Wherein the etch species is selected from the group consisting of ammonia and NF ₃ .
The method of claim 15,
Wherein the workpiece is scanned such that a portion of the workpiece is exposed to the plasma and then to heat.
The method of claim 15,
Wherein the generating and heating steps are repeated until the surface of the workpiece is cleaned.
As a method of etching the work,
Generating a plasma in an auxiliary plasma source using a gas containing an etching species, wherein the auxiliary plasma source is located in proximity to the workpiece, and ions and radicals from the plasma degenerate a portion of the workpiece. Exiting the auxiliary plasma source toward the formation of a film on the portion of the work piece; And
Using an ion beam generated using a different ion source than the auxiliary plasma source to provide energy to etch the workpiece.
The method of claim 19,
Wherein the etch species comprises halogen.
The method of claim 19,
Wherein the etch species comprises CF ₄ and oxygen.
The method of claim 19,
Wherein the etch species comprises a halogen and the autogenous oxide layer is etched.
The method of claim 19,
Wherein the ion beam comprises an inert gas.
The method of claim 19,
Wherein the ion beam is directed to the portion of the work piece while the film is being produced.
The method of claim 19,
Wherein the ion beam is directed to the portion of the work piece after the film is created.
As a method of depositing a material on a workpiece,
Generating a plasma in an auxiliary plasma source using a process gas, wherein the auxiliary plasma source is located close to the work piece, and ions and radicals from the plasma are directed toward a portion of the work piece. Exiting the source and forming a film on the portion of the work piece; And
And using an ion beam generated using an ion source different from the auxiliary plasma source to provide energy to deposit the material on the workpiece.
The method of claim 26,
Wherein the process gas comprises CH ₄ and the ion beam comprises a Group IV element.
The method of claim 26,
A method, wherein a more boxed profile is created than that produced using only the ion beam.
As a method of processing a work,
Sending ions towards the work piece using an ion beam;
Generating a plasma in an auxiliary plasma source using a process gas, wherein the auxiliary plasma source is located in close proximity to the workpiece within an end station, and ions and radicals from the plasma exit the auxiliary plasma source. Reacting with me and the surface of the work;
Heating the workpiece after the reaction, the heat repairing damage on the surface of the workpiece caused by the ion beam.
The method of claim 29,
Wherein the ion beam is used to implant ions into the workpiece.
The method of claim 29,
Wherein the workpiece is scanned such that a portion of the workpiece is exposed to the plasma and then to heat.
The method of claim 29,
The method, wherein the workpiece is heated to a temperature between 100° and 500°C.
The method of claim 29,
Wherein the process gas comprises a halogen/nitrogen mixture.
The method of claim 29,
And prior to the generating and heating the entire work piece is processed by the ion beam.
The method of claim 29,
A portion of the workpiece is processed by the ion beam while a second portion is reacted with the plasma.

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